Telephone system.



P. G. AGRELL.

TELEPHONE SYSTEM.

APPLICATION FILED FEB.15, 1908.

Patented Apr. 25, 1911.

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TELEPHONE SYSTEM. APPLIOATION'IILED 212.15, 1908.

Patented A131; 25, 1911.

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Specification of Letters Patent.

Patented Apr. 25, 1911.

Application filed February 15, 1908. Serial No. 416,072.

To all whom it may concern:

Be it known that I, FRANS GUNNAR AGRELL, a subject of the King ofSweden, and resident of Stockholm, Sweden, have invented certain new anduseful Improvements in Telephone Systems, of which the following is aspecification.

- This invention relates to telephone systems and more particularly tothat class usually designated as call distributing systems, where acalling subscriber is by means of a distributing operator, or othermeans, connected to a switching circuit controlled by an operator thatis not busy at the time, in order to equalize the work among andeventually decrease the number of operators.

One of the chief objections to such a system as heretofore devised hasbeen the difficulty to adapt the same for party line servlce.

In a call distributing system the operator does not know the number ofthe calling subscriber and, consequently, if a subscriber should call upa party on his own line (re vertedcall) the operator would find thecorresponding multiple jack indicated busy and consequently be unable tohandle such a call. The only way in which a reverted call can be handledwith the present call distributing systems is that the operator uponfindin the wanted subscribers ack busy asks the calling subscriber forhis number to ascertain that the wanted subscriber is not on the sameline as the calling. This method will, of course, lead to delays inhandling the-business so that the advantages of using the distributionsystem would be more or less off-set.

One of the objects of my invention is now to remedy the defect mentionedby the employment of means adapted to automatically indicate to anoperator that she is handling a reverted call'as soonas she tests thejack of the calling subscr ber.

In carrying out my invention in a coniplete telephone system other newobjects and results have been 'accomplished One of said new features isthat the calling cord has been provided with only two indicatorsalternatelyservmg as call, reversed call and supervisory syqnals. Insystems heretofore devised a separate indicatorv has been em ployed foreach signal.

Other objects of my invention will be in part obvious and will in partappear hereinafter in connection with the drawings accompanying thisspecification in which I have illustrated one form or embodiment of myinvention in a common battery exchange system with a combination ofcircuits and devices, many of which may be altered to meet the variousrequirements of telephone service and to adapt the same for use withother systems.

Figure 1 is a diagram showing the connections of an embodiment of myinvention in a manually operated common battery system. Fig. 2 showsdiagrammatically the connections of an embodiment where the distribution is performed. by automatically operated means, that is withoutthe help of a distributing operator.

In Fig. 1, at 12 is shown a party line having party stations 8 at theone end and carrying the local jack at, and multiple acks 5 at the otherend. The line is normally supplied with current from the common batteryover the resistance (3 on the one side and the line relay 7 on the otherside. The line relay and the resistance can be cut away from the line bymeans of the cut off relay 8, the winding of which is connected on theone side to the third conductor 9 in the multiple, on the other side toground. This third conductor 9 is connected to the sleeves of the localjack at and the multiple jacks 5. In the diagram one cord circuit drawnin heavy lines coln'iecting the answering plug 10 and the calling plug11 is shown. The answering plug 10 is positioned in a separatedistribution board having a number of answering cords 1 fl leading todifferent operators and a number of local jacks l. The calling plugs 11'are situated at multiple boards having no local jacks. At each answeringcord is a signal, in the drawing shown as a lamp 12, for indicatingwhether the operator controlling the calling end of said cord circuitis'busy or not and a disconnection signal 13, also indicated as a lamp,is provided for signaling the distribution operator that the connectionshall be taken down. The l al jacks 4 are associated with signals shownas calling lamps 14. When a subscriber upon the line ].2 calls up, for

instance, at the station 3*, current will go from the battery 35 overlead 15, resistance (3, contact 16 of the cut off relay 8 to the one.side 1 of the line and back through the subscribers instrument, theother side 2 of the line, the contact 17 of the cut-otf relay andthe'line relay 7 to ground. The line relay will thus operate closing itscontact 18 so that current now goes through the line lamp 14 indicatingthe call. The distributing operator now lifts up a plug 10, leading toan operator that is not busy at the time, as indicated by the busy lamp12, and places the same in a jack 4 thus connecting the subscribers lineto the cord circuit. 011 plugging into the calling line the relay 45 isenergized by current over the circuit 19, 44 ring side of cord throughthe local station back through the tip side relay 45 to positive pole ofbattery. The contacts- 52 and 50 are broken. The distributing operatorspart in the connection is now performed and current' goes from thebattery over lead 19, winding 22 of a relay 23, sleeve conductor 24 ofthe answering cord to the sleeve of jack 4, third conductor 9 of themultiple and the cut ofi relay 8 to ground and back to battery,indicating all the multiple jacks 5 of said line busy and operating thecut oil relay 8 and the relay 23. The cut oil relay opens the contacts16 and 17 breaking away the resistance Gand the line relay 7 from theline so that the line relay ceases to operate and, consequently, theline lamp 14 goes out. The relay 23 when operating closes the contact 25so that current goes from battery o'ver lead 19, contact 25, lead 27 andthe lamp 49, lead 26 and contact 51 of relay 47 to ground and back tobattery, lighting the lamp 49 and thus indicating to the operatorcontrolling-the plug 11 that a call is upon the cord circuit. Now theoperator controlling plug 11 notified by said signal connects hertalking set "t0 the cord circuitby throwing the key 34. The talking setand the parts of the key belongin to the same have not been shown in thed necessary for understanding the operation of the invention. When key34 was thrown contacts 39 .and 40 closed, contact 40 connecting thebattery lead 19 to a common lead 31 which branches to all the lamps 12belonging to cords controlled by this particu lar operator. The other.side ofthe lamps 12 are by means of the plug contact 33 connected toground so that the lamps 12 at such cord circuits as have not hadtheplug lifted from the seat will light indicating that the operator isbusy and that the cord should not be used. I 1

When contact 39 closed, current went from battery over lead 19, Winding36 of relay 23, 55

resistance 37, lead 38-and contact 39 of the key 34 to ground and backto battery. This winding 36 is opposing the winding 22 of same relayandthe resistance 37 is so selected that the current in winding 36neutralizes the effect of winding 22 so that relay 23 ceases to operate,breaking contactf25 and thus causing the lamp togo out. The

operator now asks for the number wanted and tests the corresponding jackin the multi ple.

Supposing now that the subscriber lagram as they are unwanted to talk toa party upon his own line, the operatorwould then find jack 5 busy asthe same is connected to battery over the winding 22 of the relay 23,but at the same time the testing current would increase the current in22 sothat said winding is no of my invention. It is only necessary toassume that the sleeve of the jack 5 is touched by a grounded conductor,for instance, the

tip of the plug 11. Current will flow through the relay 47 to ground,completing a circuit from the conductor 9 in parallel with that Ithrough the relay 8, causing an increased flow of current in the winding22 of the relay 23, but will not operate the armatures of the relay 47.

When the operator after having ascer tained that the jack 5 is notactually busy places the plug 11 into the said jack current will go frombattery over lead 19,,re1ay 21,

sleeve conductor 41 to the third conductor 9 'of the multiple andthrough the cut off relay to ground, regardless of whether said jack 5belongs to the same line as the callr ing subscriber or not.

Now the relay 21 operates, closing its contact 20, which is in shuntwith contact 25.01? relay 23 so that said relay has no effect upon thesignals as long as the'connection is made. The relay 47 will beenergized over the calling line,

breaking contact at 51 and preventing the: light-ing of lamp 49. Whenthe operator after having finished the connection throws back the key 34all the lamps 12 connected to said key will go out so that the operatoris indicated free to take a new call,

The'cord circuit ha;s',been provided with wellknown means for-supplyingcurrent to the subscribers instruments during conversation, namely, theretardation coils 44 and 45 connected to the answering end of the cordcircuit and'the retardation coils .46 and 47 connected to the callingend of the cord.

circuit and the two sides of said cord circuit are connected by means ofcondensers. .The two retardation coils 45 and 47 have been arranged asrelays and serve as such for facilitating the supervision of the calland the disconnection. For supervising the call two lamps 48 and 49, ofwhich 49 as before described also serves as callin call signal, arearranged at t e calling plug.

and reversed both connected to -battery over contacts 20 not relay 21and 25, of relay 23 and connected to ground, over the contacts 5 O-ofrelay. 45

and contact 51 of relay47, respectively, so.

that if any subscribenshould hang his re:

ceiver up, the. corresponding lamp will ,light.w I The disconnectionlamp l3 at the answering end of the cord circuit is connected to batteryover the contacts 52 upon relay 45 and 53 upon relay 47 -in series andis connected to. ground through the plug contact 54 when the plug is upso that said lamp will light as soon as both subscribers have hung uptheir receivers.

- It is not thought necessary to further trace the difliere-ntcircuitsas the same will be evident from an-inspection of the diagram.

The embodiment of my invention as shown in Fig. 2 is'distinguished fromthe one just described only by the automaticallyv operated meansemployed for connecting 'the calling line to the answering end of thecord circuit and for severing said connection after the conversation isfinished. I

been fully described in my co-pending applications Ser. Nos. 339,521 and386,901. Any other devices which fulfil the requirements of the systemcould, of course, be used 7 instead of the aforementioned devices, asthe mechanical arrangement of the connector is to a certain degreenon-essential to the operation ofthe system and it is not thought"necessary to describe the connector here further than to state that thepivoted arm 55 carries terminals 58 and 59 adapted to engage terminals60 and 61 carried by another pivoted arm 56, there being as many arms 55as there are subscribers to be accommodated by the device and as manyarms 56 as there are cord circuits assigned to said group ofsubscribers. The different arms are so positioned that the terminals ofany one of the arms 55 may engage theterminals of any one of the arms 56under certain conditions. An eleotro-magnet 7, COrIespOTlding to theline relay of Fig. 1, operates the latch 62 to release the arm 55 whichthen will fall in the direction of the arrows. The terminals 60-61 areso positioned that the same are out of reach for the terminals 58--59during this falling movement but the arms 56 can be moved in towardthecenter by means of clectro-magnets 63 so that the terminals may beengaged by a falling member 55.

The motor 57 operates in a manner fully described in the aforesaidapplications to restore the man 56 to its original position whendisconnection shall take place.

As in the diagram, Fig. 1, a party line 1 -2 having party stations 3extends in'the exchange to multiple jacks 5 and isalso connected to theterminals 58 corresponding to the tip and ring contacts of the local orcalling jack of Fig. 1. The line is normally connected to battery-overthe resistance 6 and contact 16 of a cut oft relay 8 on the one sideand'over line relay or electro-magnet 7 and contact 17 upon the cut offrelay on the other side. The cut ofi relay 8 is connected to ground ontheone side and to the third conductor 9 of the multiple on the otherside, which conductor is connected to the sleeves of the multiple jacksand to the contact 59 of the arm 55, which contact corresponds to thesleeve of the local jack 4: in Fig. 1.

The switching circuit which corresponds to the cord circuit of Fig. 1 isarranged similarly to said circuit. The contacts 60- 61 of the arms 56correspond to the local plug 10 of said circuit and the only diiter-'ence lies in the means for automatically operating said terminals.

' As before mentioned the terminals are normally out of reach of theterminals 58-59 when falling, but can be brought into an engagingposition by means of the electron'iagnet 63 operating the arm 56. Tothis end the electromagnet 63 is on the one side connected to a contact64 so situated that a contact maker or brush 65 upon the arm 55 sweepsover the same when the terminals of said arm approach the terminals ofarm 56. It said arm, like the one of the drawing, is not busy at thetime current will flow from battery 35 over the lead 19, the contact 66of the operator busy relay 30, the contact 67 of the relay 21 and thelead 68 to the magnet 63 and from there over lead 69, contacts 61 and-65to ground and back to battery so that the magnet 63 will operate movingthe arm 56 to its inner position where the terminals 58 and 59 makecontacts with the terminals 60 and 61. New current flows, from batteryover the lead 19, the winding 22 of the relay 23, the lead 24, terminals61 and 59 to the third conductor cut off relay 8 to ground cutting oilthe battery over resistance 6 and relay 7 from the subscribers line.Relay 23 also operates, closing contacts 7 0, 71 and 72. Current nowgoes from the battery over lead 19, contact 71. lead 82, contact 73 ofrelay 21 and the lead 74- to the opera tor busy relay 30 and from thereto ground. This relay 30 now operates breaking contact-66 thus cuttingaway the current from all loads 68 ot' the switching circuits controlledby this operator, so that the arm 56 goes back to its position of restwith its terminals still connected to the terminals of arm 55 and allthe arms 56 belonging to said operamr are made inaccessible for anysubgoes from the battery over lead 19 and con- 34, fiowsthrough thecompensating winding tact 40 to the operator busy relay so that the busyrelay will still bejoperated when relay 22 ceases to operate, whichhappens as soon as current, upon throwing the key 36, the resistance37,- lead 38 and the con-- tact 39 to ground, Now the lamp 49 goes out.

If in the case of a revertedcall the operator should test the sleeve ofa multiple jack however,

5, for instance, with the tip of the plug 11, additional current willflow over the winding 22 of the relay 23 so that the lamp 49 will lightagain, indicating the reverted call. When the operator after testingplaces the plug 11 into the jack 5, current will flow.

from the'battery over lead 19, relay 21, lead 41, the sleeveof the plug11 and jack 5 to the third conductor :9 of the Wanted subscribers lineindicating the same busy and operating its line relay 8 if the sameshould not, as in the case of the reverted call, be already operated.The relay 21' now operating breaks the contacts 67 and 73 and closes thecontact 76 which connects the lead- 75 to ground, so that the lamps 48and 49 now serve as supervisory signals governed solely by the operationof the relays 45 and 47.

hen the operator throws back the talking key 34, the compensatingwinding 30 will be disconnected from groundand thus the relay 23 willagain operate putting an additional ground on lead 75, but not operatingthe busy relay, as the contact 7 3 as before mentioned .is broken. Theoperator busy relay 30 thus goes back to its of rest closing the contact66 so thatthe operator can receive another call-upon another cordcircuit. The busy arm 56 is, still unresponsive to any falling arm 58asthe battery is cut off at contact 67 and will remain so as long astheconver sation goes on.

In order to facilitate the automatical dis-.

connection of terminals 5859 and 60-61 in connected on one "side overcontact of relay 23 to the battery and on the other side overcontacts52-53 of the supervisory relays 45 and 47 to ground so that when both uptheir receivers said -re-' I aspecial disconnecting relay 77 has beenput lay 77 will operate. This relay thencloses 81, of which contact.

the contacts 78, 80 .and

7 8 connects'the electro-magnet 63 to battery and contact 80 connectstheother side of saidfimagnet to ground so that it brings theafrm 56into its inner-position--where the position terminals 58 and 59 aredisconnected from the terminals 6061 by the action of the restoringmotor 57, the action of which is I contact 71 is broken so that thedisconnecting relay ceases to operate and accordingly current is cut offfrom the electro-magnet 63 so that the arm 56 goes back to its positionof rest. The supervisory lamps 48+49 still continue to light on accountof the relay 21 still beingoperated, but when the operator severs theconnection between plug 11 and,

jack 5 this relay also goes back to rest so ditions. r v 1 From theforegoing description of emthat everything' is restored to the initialconbodiments of my invention it will be seen that in a distributionsystem manually or automatically operated in accordance with the ideasherein set fortlrthe operator at the multiple board is automaticallynotified in case of a reverted call so that she may tell the callingsubscriber to hang up his-res ceiverand thus be able to the wantedsubscriber.

properly signal I As many changes could be made in the i tion designedwithout departing from the scope thereof, I intend that all mattercontained in the above description or shown in the accompanying drawingsshall be inter preted merely as an illustrative embodiment of myinvention and not in a' limiting sense.

hat I claim is: I t 1. In a telephone system, the combination with amulti-party line, of a switching cir cuit extending between twodifferently located switching devices and adapted to be connected tosaid line at one of the switching devices when said line is calling andat the other switching device when to be called,

and means including a supervising indicator which is also arranged andadapted to 'indiat said last named I cate a reverted call switching.device.

2. In a telephone system, the dombination with a multi-party line, cuitextending between cated' switching devices and adapted to be connectedto said line at one of the switching devices when said line is callingand at of a'switching i QWO difi'erently 1 the, other switching devicewhen to be called,

and means including a supervising indicator which is also arranged andadaptedto auto matic'ally indicate named switching device.

a reverted call at said last 3; In a telephone system, the combinationwith amulti-party line, of cuit extending betweentwo differently loaswitching cir I cated switch boards and adapted to be connected to saidline at one of said switch hoards when said line is calling and at theother switch board when to be called, and means including a supervisingindicator which is also arranged and adapted to indicate a reverted callat said last named switch board.

A it. In a teleplnine system, the combination with a inulti-party line,oi? a switching circuit extending between two differently located switchboards and adapted to be connected to said. line at one of said switchhoards when said line is calling and at. the other switch board whii hecalled, and

ieans including a supervising indicator which also a1 winged and adaptedto automatically indicate a reverted call at said his named switchboard.

in a telephone s; n, the combination a line of a switching circuit,automatiopt areal means adapted to connect line w .n one end or. saidswitch ng cirtor connecting the other end of ng circuit with anothercircuit, r including a supervising indicator n is also arranged andadapted to indiit said last nained end oi the switching it whether saidcircuit is connected to 1 line,

in a elephone stem, the combination with a line, of a s itching circuit,automatically operated means adapted to i connect said line with one endof said switching circuit, means or connecting the other end of saidswitching circuit with another circuit, id means including supervisingindicator also arranged and adapted to indi- 1 said last named end oithe switching whether said circuit connected to me when attempt toconnect said t named end with said line is made. 1. in a telephonesystem, the combination i a multiparty line, of a switchingcirautomatically operated means for con- Jing one end or said switchingcircuit said line, manually operated 1116 ns tor rting the other end ofsaid switching circuit with another rcuit, and means ineluding asupervising indicator which is also arranged and adapted to indicate areverted 8. in a telephone system, the combination with a hue, oi meansadapted toindicate said line busy by current flowing over said adaptedto be energized by from another circuit, means for indicating means, aswitching circuit adapted to connect with said line, means associatedwith said switching circuit and adapted to allow current to flow oversaid first named means and its shunt, a relay adapted to be energized bysaid current, a compensating winding upon said relay adapted to preventthe shunt current from energizing said relay, and a signal operated bysaid. relay.

9. in a telephone system, the combination with a line, of means adaptedto indicate said line busy by current flowing over said means fromanother circuit, a relay shunting said busy indicating means, aswitching circuit adapted to connect with said line, means associatedwith said switching circuit and adapted to allow current to flow oversaid first named means and its shunt, a relay said current, acompensating winding" upon. said relay adapted to prevent the shuntcurrent from energizing said relay, and a signal ope ated by said relay.

10. In a telephone system, the combination with switching circuitsextending between two ditl'erently located switchingdevices and adaptedto be connected with a calling line at the one switching device and witha line to becalled at the other device of means including an indicatoradapted to indicate that a calling line is connected or is going to beconnected to said switching circuit, and means including the sameindicator as that of the foregoing means for supervision of the call.

l1. Tn a telephone system, the (,Oll'lbll'iil tion with a switchingcircuit extending between two differently located switching devices andadapted to be connected with a niulti-pai y line at the one device whensaid line is calling and at the other device when to be called, of meansincl uding an indicator for supervising the call, and means includingthe same indicator adapted to indicate a reverted call.

Signed at the city of New York in the coimty oi New York and State ofNew York means shunting said busy i this 28th day of Oct. A. D. 1907.

FRANS GUNNAR AGEELL.

ii itnesses LEWIS J. Doorir'rnn B. W. COULDOCK.

drew-steamers

